The directory cannot be downloaded | Pydio version is 8.2.5

Hi, I can’t figure out why the option to download the selected directory is not shown. When I click on the directory for the first time, I see the download option but it does not work. However, when I select/click on a different directory, the DOWNLOAD button does not appear at all.

Can this be caused by server setup?

An error is also displayed quite often: session_start(): Unable to clear session lock record.

Thank you for your response.